Dental pin for tooth restoration

ABSTRACT

A serrated metal dental pin, the external surface of which is silver, with the lower portion thereof being adapted to be disposed in an opening of slightly larger transverse cross section formed in a broken tooth to be restored by amalgam. The amalgam is shaped to conform to the configuration of the brokenaway portion of the tooth. That portion of the amalgam packed in the hole surrounding the lower portion of the pin positioned therein serves to anchor the pin to the tooth. The amalgam restoration is bonded to the pin mechanically for the amalgam engages the serrated outer surface of the pin, and it is bonded chemically as well, due to the fact that the amalgam combines with the silver of the pin.

United States Patent [Ill 3,590,486

[72] Inventors l. Edward Brenner 800 W. Amerlge, Fullerton, Calif.92632; Ernest A. Beck, 1826 Chateau Ave., Anaheim, Calif. 92804 [21]Appl. No. 839,183

[22] Filed July 7, 1969 [4S] Patented July 6, 1971 [54] DENTAL PIN FORTOOTH RESTORATION 5 Claims, 8 Drawing Figs.

[52] U.S.Cl 32/15 [51] lnt.Cl A6lc 9/00 [50] FleldofSearch 32/15, 13,12, 8

[56} References Cited UNITED STATES PATENTS 1,018,803 2/1912 Anderberg32/15 2,910,772 11/1959 Chechike 32/15 3,364,575 1/1968 Baker 32/153,434,209 3/1969 Weissman 32/15 Primary Examiner Robert PeshockAttorney-William C. Babcock ABSTRACT: A serrated metal dental pin, theexternal surface ofwhich is silver, with the lower portion thereof beingadapted to be disposed in an opening of slightly larger transverse crosssection formed in a broken tooth to be restored by amalgam. The amalgamis shaped to conform to the configuration of the broken-away portion ofthe tooth. That portion of the amalgam packed in the hole surroundingthe lower portion of the pin positioned therein serves to anchor the pinto the tooth. The amalgam restoration is bonded to the pin mechanicallyfor the amalgam engages the serrated outer surface of the pin, and it isbonded chemically as well, due to the fact that the amalgam combineswith the silver of the pin.

DENTAL PIN FOR Toorn RESTORATION BACKGROUND OF THE INVENTION 1. Field ofthe Invention An improved dental pin for holding an amalgam restorationin position on a tooth that has been partially broken away.

'2. Description of the Prior Art Heretofore in the amalgam restorationof a broken tooth, it has been common practice to drill holes in thetooth in which stainless steel wires or pins are positioned. The pinshave been cemented in such drilled holes, or held therein by a frictionfit. The exterior surfaces of these pins usually have been serrated.

The usual practice was to pack the amalgam about the projecting portionsof the pins to restore the tooth to its original configuration, with theamalgam engaging the serrations formed in the pin, whereby a mechanicalbond with the pin was effected when the amalgam solidified. The mecuryof the amalgam does not combine chemically with the stainless steel ofthe pin, and as a result, no cohesion is effected between the amalgamand the stainless steel.

The present invention comprises a serrated dental pin provided with anexternal silver surface, which pin overcomes the disadvantages found inprior art devices of the type described, for the amalgam serves to notonly anchor the pin hereinafter described to a tooth, but also resultsin not only a mechanical but a chemical bond of the amalgam with thepin.

SUMMARY OF THE INVENTION A serrated metal dental pin having an externalsilver surface, the lower end of which pin is disposed in a hole drilledin a broken tooth. Amalgam is packed around that portion of the pinpositioned in the hole to mechanically and chemically bond this pinportion to the tooth. The body of amalgam that is used to fill thebroken-away portion of a tooth to effect the restoration is mechanicallyand chemically bonded to the projecting section of. the pin. Themechanical bond occurs when amalgam in a plastic state is forced intothe serrations whereby the amalgam mechanically interlocks with the pinwhen the amalgam solidifies.

The chemical bond occurs when the amalgam dissolves a part of the silverto form a silver-enriched amalgam zone which merges both into the silverand the original amalgam, with the amalgam and silver-enriched amalgam,when solidified, being integrally and metallurgically connected to saidsilver.

A major object of the present invention is to provide an improved dentalpin in which a circumferentially serrated wire of stainless steel orother corrosion-resistant metal or metal alloy is enveloped in a layerof silver, which pin is anchored in a drilled hole in a broken tooth,both mechanically and chemically by amalgam, with the body of amalgamserving to restore the broken-away portion of the tooth and providingthe restoration that is likewise mechanically and chemically bonded tothe pin.

Another object of the invention is to provide a silver'enveloped dentalpin for use in repairing broken teeth wherein the body of amalgamdefining the restoration and the silver layer surrounding the projectingportion of the pin metallurgically merge, with the amalgam restorationbeing longitudinally movable relative to the pin, only if the silverenvelope about the pin is actually broken at a position intermediate theends thereof.

Yet still another object of the invention is to provide asilver-enveloped dental pin with which amalgam is used to not onlymechanically and chemically anchor at lower portion of the pin in a holedrilled in a broken tooth. but also to define the restoration andmechanically and chemically bond the same to u projecting portion ofthepin. I

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of atooth, a portion of which has been broken away, which tooth is to berestored by amalgam;

FIG. 2 is the same view of the tooth shown in FIG. I illustrating one ofa number of openings drilled therein;

FIG. 3 is the same perspective view of the tooth shown in FIG. 2,showing the improved dental pin disposed therein;

FIG. 4 is the same perspective view of the tooth and pin shown in FIG. 3illustrating the manner in which amalgam is forced around the lowerportion of the pin in the hole to mechanically and chemically bond thepin to the tooth;

F IG. 5 is a perspective view of the tooth, with one of the improvedpins projecting upwardly from a hole in the tooth, and in which hole thelower portion of the pin is supported and anchored by amalgam;

FIG. 6 is a perspective view of the tooth and amalgam restoration, withthe restoration being held on the tooth by a number of spaced, upwardlyprojecting pins;

FIG. 7 is a fragmentary, vertical, cross-sectional view of the tooth andrestoration, taken on the line 7-7 of FIG. 6, illustrating the manner inwhich the pin and a portion of the amalgam hold the tooth andrestoration together as an integral unit; and

FIG. 8 is a fragmentary, transverse cross-sectional view of the device,taken on the line 8-8 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT A molar A is shown in FIG. 1, aportion 8 of which has been broken away. In FIG. 6 it will be seen thatthe broken-away portion 8 has been filled with a body of amalgam, whichis shaped to the same configuration as the portion of the molar A whichhad been broken away.

Restoration of the molar A from the condition shown in FIG. 1 to thatillustrated in FIG. 6.may be accomplished by the following procedure.During the restoration operation, a number of spaced holes C (FIGS. 2and 6) are drilled in the dentine of the molar A. The holes C preferablyare not in parallel relationship, and one of the holes is shown (FIG. 2)being drilled in the molar A by use of a power-driven drill D.

The dental pin E of the present invention is substantially longer thanthe depth of the hole C in which it will be positioned. Pin E includes awire 10, preferably about 0.020 inch in diameter, on the exteriorsurface of which circumferentially extending serrations I2 are formed.Wire 10 is preferably formed from stainless steel or other high strengthmetal alloy that is corrosion-resistant. By electrodeposition, the wireI0 is completely enveloped in a layer 14 of silver or a high contentsilver alloy.

After the holes have been drilled into the tooth A, a pin E is placed ineach hole. Each hole is slightly large in transverse cross section thanthat of the pin E to be inserted therein by use of a suitable instrumentF, as illustrated in FIG. 3. After each pin E has been inserted in ahole C, the annulus-shaped space (not shown) existing between theexterior surface of the pin and the wall of the hole is tampedl full ofamalgam B' by the use of the instrument G shown in FIG. 4. When theamalgam B' is tamped into the annulus-shaped space in a plastic state,it is easily forced into full surface contact with the silver layer 14.

The mercury in the amalgam B dissolves an exterior portion of the silverlayer 14, and by so doing, forms a second silver-enriched amalgam at theinterface of the silver and the amalgam B. The silver-enriched amalgamand the original amalgam embody substantially the same physicalproperties when they solidify. Thus, it will be seen that thesilver-enriched amalgam merges into that portion of the silver in layer14 that has not been dissolved, and also merges into the originalamalgam B. Upon solidification of the silver-enriched amalgam and theamalgam B, the remaining silver in layer 14 is metallurgically bonded tothe amalgam B.

The amalgam B and silver-enriched amalgam in each hole C aremechanically bonded to the pin E inasmuch as they engage mechanicallybonded to the pin E inasmuch as they engage and interlock with theserrations l2 defined thereon. When the amalgam B and silver-enrichedamalgam solidify, they tend to expand slightly, whereby the amalgamsfrictionally grip the wall of the hole C with great tenacity and aredifficult to remove therefrom.

After the pins E have been anchored in the holes C in the mannerdescribed, a quantity of amalgam is shaped to define the body B, asillustrated in FIG. 6. The body B completely envelops the upwardlyprojecting portions of the pins E. The amalgam of body B partiallydissolves the silver in layers 14 on the upwardly projecting portions ofthe pins E, with the zone of silver-enriched amalgam resulting therefrommerging both into the silver of layer 14 and the amalgam defining thebody B. Thus, when the amalgam of body B and the zone of silverenrichedamalgam solidify, the layer.l4 of silver enveloping the serratedstainless steel wire is metallurgically bonded to the amalgams. The bodyB can only be moved longitudinally relative to the wires 10 by breakingthe enveloping silver layers at some position intermediate the endsthereof.

Due to the metallurgical bond between the amalgam defining body B andthe silver enveloping the serrated wires 10, it is highly desirable thatthe layers of silver 14 be sufficiently thick that the inner portionsthereof remain in the unamalgamated state. Longitudinal movement of thebody B relative to the upwardly projecting portions of the pins E isalso difficult due to the positive interlocking of the solidifiedamalgam of body B and the silver-enriched amalgam with the serrations12, which form a mechanical as well as chemical bond with the pins.

In the manufacture of the pins E, the serrated wire 10 is first formed,with the layer 14 of silver or silver alloy being thereafterelectrodeposited thereon to a thickness to achieve the operationaladvantages described herein. The instrument G includes an elongatehandle having an angularly disposed lower portion 22, which developsinto body 24 of larger transverse cross section. A bore 26 extendstransversely through body 24. The bore 26 is of such transverse crosssection that it slidably engages the projecting portion of each pin E.The lower surface 28 of body 24 may be used to tamp amalgam into thehole C about pin E, when the body is alternately moved upwardly anddownwardly relative to the tooth A.

We claim:

1. In combination with a tooth having a broken-away portion, whichtoothis restored to its original configuration by a body of amalgam, with atleast one hole being drilled into the dentine of said tooth that is incommunication with said broken-away portion, a dental pin for holdingsaid body in position in said tooth, which pin includes:

a. a circumferentially serrated wire substantially longer than the depthof said hole, with said wire being formed from a rigid metallic materialthat is substantially corrosion-resistant;

b. a layer of high content silver metal which envelops said wire, withthe transverse cross section of said wire and said layer enveloping samebeing substantially less than that of said hole; and

c. a quantity of plastic amalgam in said hole that is in surface contactwith said layer when a lower portion of said pin is disposed in saidhole with an upper part of said pin projecting from said hole andcompletely disposed in said body when in a plastic state, which amalgamin said hole and in said plastic amalgam body dissolves a part of saidsilver in said layer to form a zone of silver-enriched amalgam thatmerges both into the undissolved silver of said layer aswell as intosaid amalgam that has been so enriched, with said amalgam andsilver-enriched amalgam, when metallurgically solidified, bonding saidbody to said pin by said silver, silver-enriched amalgam, and thenonsilverenriched amalgam forming an integral mass that preventslongitudinal movement of said body relative to said pin, and with saidbody being further restrained from longitudinal movement relative tosaid pin due to the mechanical engagement of said solidified amalgamswhich engage said serrations defined by said silver layer. 2. A dentalpm as defined in claim 1 wherein said wire is of stainless steel.

3. A dental pin as defined in claim 1 wherein said high silver contentmetal is silver.

4. A dental pin as defined in claim 1 wherein said layer is sufiicientlythick that a portion thereof remains unamalgamated after contact withsaid amalgam.

5. A dental pin as defined in claim 1 wherein said layer iselectrodeposited on said wire.

1. In combination with a tooth having a broken-away portion, which toothis restored to its original configuration by a body of amalgam, with atleast one hole being drilled into the dentine of said tooth that is incommunication with said broken-away portion, a dental pin for holdingsaid body in position in said tooth, which pin includes: a. acircumferentially serrated wire substantially longer than the depth ofsaid hole, with said wire being formed from a rigid metalLic materialthat is substantially corrosionresistant; b. a layer of high contentsilver metal which envelops said wire, with the transverse cross sectionof said wire and said layer enveloping same being substantially lessthan that of said hole; and c. a quantity of plastic amalgam in saidhole that is in surface contact with said layer when a lower portion ofsaid pin is disposed in said hole with an upper part of said pinprojecting from said hole and completely disposed in said body when in aplastic state, which amalgam in said hole and in said plastic amalgambody dissolves a part of said silver in said layer to form a zone ofsilver-enriched amalgam that merges both into the undissolved silver ofsaid layer as well as into said amalgam that has been so enriched, withsaid amalgam and silver-enriched amalgam, when metallurgicallysolidified, bonding said body to said pin by said silver,silver-enriched amalgam, and the nonsilver-enriched amalgam forming anintegral mass that prevents longitudinal movement of said body relativeto said pin, and with said body being further restrained fromlongitudinal movement relative to said pin due to the mechanicalengagement of said solidified amalgams which engage said serrationsdefined by said silver layer.
 2. A dental pin as defined in claim 1wherein said wire is of stainless steel.
 3. A dental pin as defined inclaim 1 wherein said high silver content metal is silver.
 4. A dentalpin as defined in claim 1 wherein said layer is sufficiently thick thata portion thereof remains unamalgamated after contact with said amalgam.5. A dental pin as defined in claim 1 wherein said layer iselectrodeposited on said wire.